US-12616981-B2 - Systems and methods for fluid separation interface control using color-based optical measurements

US12616981B2US 12616981 B2US12616981 B2US 12616981B2US-12616981-B2

Abstract

A fluid separation device includes a centrifugal separator configured to receive a centrifugal separation chamber of a disposable fluid flow circuit, a pump system configured to convey a fluid into the centrifugal separation chamber and to remove a separated fluid component from the centrifugal separation chamber via an outlet, a color-based interface monitoring system configured to determine an interface position between separated fluid components continuously flowing through the centrifugal separation chamber based on dominant wavelength measurements of layers of separated fluid components during a centrifugal separation procedure, and a controller configured to measure the dominant wavelengths of the layers, calculate a duration as a color time for each measured dominant wavelength, set target color times, calculate error signals and calculate control signals to adjust the pump system to control the flow rate and interface position.

Inventors

Benjamin E. Kusters

Assignees

FENWAL, INC.

Dates

Publication Date: 20260505
Application Date: 20230112

Claims (17)

1 . A fluid separation device, comprising: a centrifugal separator configured to receive a centrifugal separation chamber of a disposable fluid flow circuit, the centrifugal separation chamber having an annular channel and a ramp extending from a high-G side wall portion toward a low-G side wall portion across at least a portion of the annular channel of the centrifugal separation chamber; a pump system configured to convey a fluid into the centrifugal separation chamber, and to remove a separated fluid component from the centrifugal separation chamber; an outlet associated with the centrifugal separation chamber for removing at least a portion of the separated fluid component from the centrifugal separation chamber; a color-based interface monitoring system configured to determine an interface position between separated fluid components continuously flowing through the centrifugal separation chamber based on color measurements of layers of the fluid during a centrifugal separation procedure; wherein the color-based interface monitoring system further comprises a light source directed toward the ramp in the centrifugal separation chamber and a color measurement device which measures colors of dominant wavelengths of reflected light over time; and a controller configured to: control the pump system to convey a fluid into the centrifugal separation chamber; control the centrifugal separator to separate the fluid in the centrifugal separation chamber into layers of separated fluid components with the interface position located between the layers of separated fluid components; utilize the light source and color measurement device to measure a color of each layer of the respective separated fluid components via a dominant wavelength of reflected light; calculate as a color time a duration of time over which the reflected light is present for each measured dominant wavelength associated with the respective layers of separated fluid components; set a predetermined target color time as a setpoint for each layer; calculate an error signal; and utilize the error signal and calculate proportional-integral-derivative terms and a control signal that changes a pump system setting so as to adjust the interface position.
2 . The fluid separation device of claim 1 , wherein the light source further comprises a broadband light source.
3 . The fluid separation device of claim 2 , wherein the broadband light source includes a minimum of all wavelengths in a visible range of approximately 400-700 nm.
4 . The fluid separation device of claim 2 , wherein the broadband light source further comprises at least one optical fiber.
5 . The fluid separation device of claim 2 , wherein the color measurement device further comprises a spectrometer, and the broadband light source and spectrometer are configured to be connected to an optical fiber bundle including at least one optical fiber which carries light from the broadband light source to the fluid in the centrifugal separation chamber and at least one optical fiber that carries light reflected by the fluid in the centrifugal separation chamber to the spectrometer.
6 . The fluid separation device of claim 5 , wherein the optical fiber bundle includes a plurality of optical fibers that carry light from the broadband light source and are arranged around the at least one optical fiber that carries reflected light to the spectrometer.
7 . The fluid separation device of claim 5 , wherein the optical fibers of the optical fiber bundle are placed at a selected acute angle relative to a surface of the ramp in the centrifugal separation chamber containing the fluid being processed.
8 . The fluid separation device of claim 7 , wherein the selected acute angle is an angle between 30° and 60°.
9 . The fluid separation device of claim 1 , wherein the error signal for a selected layer is equal to the target color time minus the calculated color time for the selected layer.
10 . The fluid separation device of claim 1 , wherein the fluid comprises anticoagulated whole blood, the interface is between red blood cells and plasma, and the separated fluid component is the plasma.
11 . The fluid separation device of claim 1 , wherein the fluid separation device is configured to process blood to separate at least one cellular component from plasma.
12 . The fluid separation device of claim 1 , wherein the controller is further configured to repeatedly: utilize the light source and color measurement device to measure a color of each layer of the respective separated fluid components via a dominant wavelength of reflected light; calculate as a color time a duration of time over which the reflected light is present for each measured dominant wavelength associated with the respective layers of separated fluid components; set a predetermined target color time as a setpoint for the interface position; calculate an error signal; and utilize the error signal and calculate proportional-integral-derivative terms and a control signal that changes a pump system setting so as to adjust the interface position.
13 . The fluid separation device of claim 1 , wherein the fluid comprises anticoagulated whole blood, the interface is between red blood cells and platelet-rich plasma, the separated fluid component is the platelet-rich plasma, and the controller is further configured to repeatedly complete a routine of calculating the duration as the color time for the measured dominant wavelength of the platelet-rich plasma layer, calculating the error signal, utilizing the error signal to calculate proportional-integral-derivative terms and to calculate the control signal, and using the calculated control signal to change the pump system setting to adjust the interface position.
14 . A blood separation system, comprising: a centrifugal separator configured to receive a centrifugal blood separation chamber of a disposable fluid flow circuit, the centrifugal separation chamber having an annular channel and a ramp extending from a high-G side wall portion toward a low-G side wall portion across at least a portion of the annular channel of the centrifugal separation chamber and to process blood to separate at least one cellular component from plasma; a pump system configured to move the plasma in the disposable fluid flow circuit; an outlet associated with the blood separation chamber for removing at least a portion of the plasma from the blood separation chamber; a color-based interface monitoring system configured to directly monitor the interior of the blood separation chamber and to determine an interface position between the separated component and the plasma during a centrifugal separation procedure; wherein the color-based interface monitoring system further comprises a light source directed toward the ramp in the centrifugal separation chamber and a color measurement device which measures colors of dominant wavelengths of reflected light over time; and a controller configured to: control the pump system to convey a fluid into the centrifugal separation chamber; control the centrifugal separator to separate the blood in the centrifugal separation chamber into layers of plasma and the separated at least one cellular component with the interface position located between the layers; utilize the light source and color measurement device to measure a color of each layer via a dominant wavelength of reflected light; calculate as a color time a duration of time over which the reflected light is present for each measured dominant wavelength associated with the respective layers; set a predetermined target color time as a setpoint for a selected layer; calculate an error signal equal to the target color time minus the calculated color time for the selected layer; calculate proportional-integral-derivative terms and a control signal; and utilize the error signal and calculate proportional-integral-derivative terms and a control signal that changes a pump system setting so as to adjust the interface position.
15 . The fluid separation device of claim 14 , wherein the light source further comprises a broadband light source.
16 . The fluid separation device of claim 15 , wherein the broadband light source includes a minimum of all wavelengths in a visible range of approximately 400-700 nm.
17 . The fluid separation device of claim 15 , wherein the color measurement device further comprises a spectrometer, and the broadband light source and spectrometer are configured in an optical fiber bundle including at least one optical fiber which carries light from the broadband light source to the plasma and the at least one cellular component in the centrifugal separation chamber and at least one optical fiber that carries light reflected by the plasma and the at least one cellular component in the centrifugal separation chamber to the spectrometer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63/299,654, filed Jan. 14, 2022, the contents of which are incorporated by reference herein in their entirety. BACKGROUND Field of the Disclosure The present disclosure relates to centrifugal separation of a biological fluid. More particularly, the present disclosure relates to improved systems and methods for control of an interface position between separated fluid components during fluid separation procedures. Description of Related Art Various blood processing systems now make it possible to collect particular blood constituents, rather than whole blood from a blood source, such as a human donor or patient. Typically, in such systems, whole blood is drawn from a source, the particular blood component or constituent is separated, removed and collected, and the remaining blood constituents are returned to the source. Removing only particular constituents is advantageous when the blood source is a donor, because potentially less time is needed for the donor's body to return to normal or pre-donation levels. Also, donations of particular blood components or constituents may be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for transfer and/or therapeutic treatment or health care. Whole blood is typically separated into its constituents through centrifugation. This requires that the whole blood be passed through a centrifuge assembly or centrifugal separator after it is withdrawn from, and before it is returned to, the blood source. To avoid contamination and possible infection of the source, the blood is preferably contained and processed within a disposable, sealed, sterile fluid flow circuit or fluid processing assembly during the entire centrifugation process. Typical blood processing systems thus include a permanent or reusable centrifuge assembly containing hardware (centrifuge, drive system, pumps, valve actuators, programmable controller, and the like) that rotates a centrifugal separator and controls the flow through the disposable, sealed and sterile fluid flow circuit that is mounted on and in cooperation with the hardware. The centrifuge assembly engages and rotates a centrifugal separation chamber of the disposable fluid processing assembly during a collection procedure. The blood, however, makes actual contact only with the fluid processing assembly, which assembly is used only once and then discarded. Prior to or shortly after loading a disposable fluid flow circuit into the centrifuge assembly, the operator typically enters, for example, by means of a touch screen or other user interface system, a particular processing protocol to be executed by the system (e.g., a procedure wherein platelets are separated from whole blood and collected) and other parameters (e.g., the weight of the donor, the desired volume of the separated blood component to be collected, etc.). When the system has been programmed, the operator phlebotomizes a donor and the system carries out the procedure, under the supervision of the operator. As the centrifuge assembly rotates the centrifugal separation chamber of the disposable fluid flow circuit, the heavier (greater specific gravity) components of the whole blood in the separation chamber, such as red blood cells, move radially outwardly away from the center of rotation toward the outer or “high-G” wall of the separation chamber. The lighter (lower specific gravity) components, such as plasma, migrate toward the inner or “low-G” wall of the separation chamber. Various components can be selectively removed from the whole blood by including appropriately located channeling structures and outlet ports in the separation chamber of the disposable fluid flow circuit. For example, therapeutic plasma exchange involves separating plasma from cellular blood components, collecting the plasma, and returning the cellular blood components and a replacement fluid to the blood source. Alternatively, red blood cells may be harvested from the separation chamber and the rest of the blood constituents returned to the donor. Other processes are also possible including, without limitation, platelet collection, red blood cell exchanges, plasma exchanges, etc. Proper separation requires, however, that the interface between the separated components be located within a particular zone between the high-G and low-G walls of the separation chamber. For example, when performing a therapeutic plasma exchange procedure, the interface between the plasma and the cellular blood components affects the performance of the system. If the interface is located too close to the low-G wall, then the collected plasma may become unduly populated or contaminated by cellular blood components. On the other hand, if the interface is located too far from the l